| County | Reported* | Tested | Positive | % Tested Positive |
| Alameda | 476 | 6 | 6 | 100% |
| Alpine | - | - | - | - |
| Amador | 2 | - | - | - |
| Butte | 50 | 11 | - | - |
| Calaveras | 8 | - | - | - |
| Colusa | 11 | 3 | - | - |
| Contra Costa | 450 | 53 | 3 | 6% |
| Del Norte | - | - | - | - |
| El Dorado | 60 | 14 | - | - |
| Fresno | 130 | 17 | 11 | 65% |
| Glenn | 6 | - | - | - |
| Humboldt | 15 | - | - | - |
| Imperial | 3 | - | - | - |
| Inyo | 1 | - | - | - |
| Kern | 37 | 4 | 1 | 25% |
| Kings | 16 | - | - | - |
| Lake | 17 | 9 | - | - |
| Lassen | 1 | - | - | - |
| Los Angeles | 650 | 85 | 2 | 2% |
| Madera | 12 | 3 | - | - |
| Marin | 69 | 3 | - | - |
| Mariposa | - | - | - | - |
| Mendocino | 9 | - | - | - |
| Merced | 37 | 3 | - | - |
| Modoc | - | - | - | - |
| Mono | 1 | - | - | - |
| Monterey | 31 | 5 | - | - |
| Napa | 24 | 6 | - | - |
| Nevada | 27 | 2 | - | - |
| Orange | 351 | 122 | 2 | 2% |
| Placer | 191 | 69 | 5 | 7% |
| Plumas | 3 | - | - | - |
| Riverside | 150 | 42 | - | - |
| Sacramento | 649 | 255 | 23 | 9% |
| San Benito | 4 | 1 | - | - |
| San Bernardino | 107 | 27 | - | - |
| San Diego | 365 | 130 | 18 | 14% |
| San Francisco | 77 | 4 | - | - |
| San Joaquin | 170 | 45 | 6 | 13% |
| San Luis Obispo | 50 | 9 | - | - |
| San Mateo | 459 | 130 | - | - |
| Santa Barbara | 45 | 18 | - | - |
| Santa Clara | 665 | 141 | 25 | 18% |
| Santa Cruz | 76 | 26 | - | - |
| Shasta | 16 | 4 | - | - |
| Sierra | 1 | - | - | - |
| Siskiyou | 3 | - | - | - |
| Solano | 123 | 24 | 2 | 8% |
| Sonoma | 129 | 14 | - | - |
| Stanislaus | 137 | 13 | 1 | 8% |
| Sutter | 19 | 5 | 1 | 20% |
| Tehama | 8 | - | - | - |
| Trinity | - | - | - | - |
| Tulare | 62 | 18 | 7 | 39% |
| Tuolumne | 4 | - | - | - |
| Ventura | 112 | 18 | 1 | 6% |
| Yolo | 168 | 33 | 1 | 3% |
| Yuba | 24 | 7 | - | - |
| State Totals | 6311 | 1379 | 115 | 8% |
* Birds in a die-off are not included in reported totals because the deaths are not related to WNV. A die-off is defined as a group of 10 or more same species dead birds unless the species is American Crow.
Source: Vector-Borne Disease Section, California Department of Public Health